This project examines the effects of psychological disorder and social need on patterns of medical care utilization, physician disposition of patient problems, treatments provided, and processes of referral to psychiatric services. Three samples were surveyed in a population area that was substantially rural but served by a single large multispecialty group practice: a sample of 1026 persons representative of the community population, 114 patients in this population seeking psychiatric care, and 316 Medicaid recipients residing in the same geographic area. Data from patient interviews have been merged with information from medical and pharmaceutical records for the 12-month period following interview. Psychological disorder, social need, sociodemographic characteristics, and group structure variables are used as predictors of patterns of utilization of medical and psychiatric services, disposition and referral by primary care practitioners to specialized psychiatric services, prescription of psychoactive drugs by primary care physicians and psychiatrists, and use of nonprescription drugs. Patterns are examined in relationship to various financial arrangements for services including prepaid group practice and fee for service, and whether the patient receives medical care from the centralized clinic or from its satellites. A major focus of the study is the way in which management of psychological disorder and social need by the mainstream medical care system affects patterns of subsequent utilizattion of medical resources and patient outcomes.